1. Field of the Invention
The present invention relates to a color management technique used in a process in which printing plates are formed on the basis of binary image data obtained by subjecting multi-value image data to RIP (Raster-Image-Processing) and ink is applied to the printing plates to print an image on a sheet of printing paper.
2. Description of the Background Art
Conventionally, in a color monitor of a computer for displaying image and a color printer or the like for providing a color output by using the image data, there has been a problem in which even when the same image data is used, reproduced colors are not made coincident with each other. In recent year, a color management is carried out so as to solve this problem.
The color management is a technique in which a device profile representing color-reproduction characters (hereinafter, referred to simply as “profile”) is prepared for each of digital input devices and digital output devices, and based upon this profile, image data is color-converted through device-independent colors that are independent of the devices. With respect to such profiles, the ICC profile is standardized by the ICC, which is the international standardization organization.
In contrast to digital devices such as the above-mentioned color monitors and color printers, the color management using profiles has not been applied to general printing presses such as planographic offset printing presses. One of the reasons for this is that the printing plate making routine (or prepress routine) is carried out independently from the printing routine and, in most cases, the printing plates are still formed through an analog exposing process. Moreover, another problem is that, in general printing presses, there is a great difference in color reproducing characteristics depending on printing conditions (such as kinds of ink and printing paper). Therefore, in the conventional printing presses, a printed material is read with a color measurement console, etc. to measure actual print colors, and the amount of ink, damping water, etc. are adjusted on the printing press side so as to set the print colors to predetermined values, thereby managing the print colors.
On the other hand, a printing press comprising a printing plate recording device for directly forming an image on a printing plate based upon digital image data, i.e., a so-called CTP (Computer-To-Plate) system, have been put into practical use. As such a printing press equipped with a CTP device has been widely used, there are demands for skill-less color management processes for printed materials.